DE1720942A1 - Process for the polymerization of acrylonitrile with at least one conjugated aromatic olefin - Google Patents

Description

The invention relates to copolymers of conjugated aromatic olefins with a high proportion of acrylonitrile.

Such aromatic olefins can be very easily with a high proportion of acrylonitrile copolymerize »so that the part of the copolymer formed at the beginning of the reaction to the disadvantage of the part of the copolymer formed at the end of the reaction is enriched with the aromatic olefin. The one at the end The copolymer part formed during the reaction can therefore have the disadvantageous properties of crystalline polyacrylonitrile,

New documents (Art 7 11 Para. 2 No. 1 Sau 3 dM And «un # * o ··. V. 4. S. lflttZI

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if not careful addition of the monomers (or at least the aromatic olefin) to the reaction medium is carried out throughout the polymerization. In British Patent 663,268 there is such a method described, after acrylonitrile and styrene or e (-methylstyrene an aqueous medium containing a water-soluble peroxo catalyst and a dispersing agent , the reflux tempera door are fed, and in such Amounts that a substantially constant reflux temperature is maintained in the aqueous medium. Sin A more expedient method is that the heat of polymerization during the reaction by isothermal Calorimetry measures and the monomers share in the reaction medium " adds moderately depending on the heat generated.

British patent specification 663 268 also contains information that copolymers with 40 to 80 wt .-? f of the acrylonitrile are suitable for the production of injection molded curpers because of the extraordinary flexural strength and tensile strength combined with extraordinary clarity. These boundaries correspond molar ratios from 1.3 to 7.9 for units τοη acrylonitrile and styrene bow · from 1.5 to 8.9 for units of acrylonitrile and fc-methylstyrene oil. There are animal examples such copolymers are described, and the relevant information about them is summarized below:

Example no. 1 55 ο * 1 6th Comonomer Styrene 2, fib-He thy is tyrol Styrene Acrylonitrile (weight-jl) 65 17, 40 41.5 46.7 Molar ratio 3.65 9, 50 1.58 1.70 Flexural strength
(fcgf / mm ² ) 18.80 10 16.40 16.20 tensile strenght 9.30 8.70 8.80

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No information was given on the molecular weight of these products and compression molding was the only molding process by which they were processed. But if the test is repeated according to Example 3 of the mentioned patent, it is found that the copolymer thus obtained a reduced Viecoeität of 5.14 (measured in O, 5 / $ - strength solution in dimethylformamide at 25 ⁰ C) and a melt viscosity of 23 kP (measured at 26O ⁰ C) and a shear rate of 1000 / sec.) ·

A copolymer of acrylonitrile and at least one conjugated aromatic olefin, the units of the aromatic olefin being uniformly distributed in the polymer molecules, is easy to inject and has excellent mechanical properties if, according to the invention, the molar ratio of units of acrylonitrile to units of aromatic olefin in the copolymer between 2: 1 and 6: 1, and the reduced Tiscosität of the copolymer (measured in 0.5> - strength solution in dimethylformamide at 25 ⁰ C?) is between 0.5 and 1.2, when the molar ratio less than 4: Is 1, and is between 0.5 and 1.8 when the molar ratio is 4 or more.

The invention thus relates to a process for the polymerization of acrylonitrile with at least one conjugated aromatic λ see olefin, which is characterized in that the monomer batch containing the aromatic olefin is added to a polymerization reaction mixture containing acrylonitrile and aromatic olefin at a rate that is achieved by the Free / grounding heat of polymerization is determined to obtain a copolymer of acrylonitrile with uniformly distributed units of aromatic olefin, which has a molar ratio of acrylonitrile to aromatic olefin units between 2 and 6 and a reduced viscosity

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(measured at 25 ^° C. in a 0-5 solution in dimethylformamide) between 0.5 and 1.2 at a ratio of less than 4 and between 0.5 and 1.8 at a molar ratio of 4 or more .

Bas conjugated aromatic olefin is selected from those of the formula: OH ₂ SOiUAr and acenaphthylene, indene and coumarone. In this formula, R represents a hydrogen atom or a methyl group, while Ar represents an optionally ring-substituted radical of aromatic type with not more than 3 rings, each substituent optionally present containing not more than 4 carbon atoms. The following can be mentioned as examples of such olefins: styrene, o-methyletyrene, o-methylstyrene, m-methyletyrene, p-methylstyrene, m-vinylphenol, p-trimethylsilylstyrene, 2,5-dimethylstyrene, p-methoxyetyrene, 1-vinylnaphthalene, p-dimethylaminostyrene, ar-dibromostyrene, p-acetamidostyrene, 2-vinylthiophene, 3-tinylphenanthrene, 2-methyl-5-vinylpyTidine and N-vinylcarbazole.

It has been found with copolymers of this type that while the molten viscosity increases uniformly with increasing molecular weight (represented by the reduced viscosity), the impact strength approaches a maximum value, beyond which it hardly or not at all exceeds with further increase in molecular weight. This point is reached at a reduced viscosity below 1.2 when the molar ratio (of acrylonitrile to aromatic olefin) is less than 4, and at a reduced viscosity below 1.8 when the molar ratio is 4 or more but less than 6 ·

The size of this maximum impact strength depends on the Composition of the copolymer from, with higher impact strength values are achieved, the higher the molar ratio of Is acrylonitrile to aromatic olefin. The lowest molecular weight at which a copolymer of a given composition

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setting has its maximum impact strength corresponds a certain melt viscosity, and this minimum Melt viscosity also increases with increasing molar ratio from acrylonitrile to aromatic olefin in the copolymer.

These determinations can be made on the basis of the drawings explain.

In the graphic representation according to Pig. 1, the ordinates represent the melt viscosity and the abscissas represent the molecular weight, namely of aorylnitrile / styrene copolymers according to the invention with a molar ratio of 3-65 (upper curve) and of likewise uniform but equal molar acrylonitrile / styrene copolymers (lower curve) . The Schmelzvisoosität each was measured at 26O ⁰ C and a shear rate of 1000 / sec and is reported in kP. Bas average molecular weight is (measured in D, 5J6-strength solution in dimethylformamide at 25 ⁰ C) by a reduced Viscoeität shown.

In the graph according to FIG. 2, the ordinates represent the impact strength and the abscissas represent the reduced viscosity for the same two series of copolymers, with the upper curve referring to the high acrylonitrile copolymer relates. The impact strength was measured with an unnotched test rod 0.9 cm wide and 0.3 cm thick, which was placed horizontally so that the narrow side was facing up and a broad set on two vertical supports with a distance of 3 * 8 cm. The test rod was in the middle the other broad side was hit by a horizontally moving pendulum that was hit by a fleas of 30 cm fell and had more than enough fall energy to break the staff. From the residual energy of the pendulum the

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. The energy required to break the test data was calculated, and this was divided by the effect volume (1/9 3.8 χ 0.9 ζ 0.3 ca '). The relevant value (in Joule / ora ³ ) represents the energy which is necessary to cause the formation of heterogeneous cracks.

You creation neoh 71g. 3 selgt impact strength (ordinates) versus Schmeliviaooaität (Abazlaaen) for the same two series of copolymers according to the data from deli Figures 1 and 2, with the upper lurre again eof das Copolymer with high acrylonitrile content. £ e let tr * Obviously, there is one for the maximum impact minimal Sohmeleviacoaitat there. __

In the curve according to Ed. 4, dl · Ordlneten may 1 - Te Sehlagsählgkelt and the Abesieaen MolarverbäUtnla bsi uniform acrylonitrile / styrene copolymers.

The representation according to fl. 5 shows sobmelaviacoaity (Ordlnaten) against Holar relation (Abaaisaen) and gives the minimum Scheeleviacoeitllt at which an acrylonitrile / styrene copolymer of the respective molar ratio possesses the macimal impact ability. The minimum reduced yiscoaity is determined in the same way, fig "6" the relationship between reduced Tiecoaltat and molar ratios, the dashed line indicating the extent of the claimed selection.

The impact strength depends on the Holer ratio of the acrylonitrile much more dependent than you would on the information given Examples 3, 4 and 6 of British Patent 663 would have suspected. VIe can be seen from Figure 4, the increases Impact strength quickly up to a molar ratio Acrylonitrila of about 6, over which the impact again

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falls. JecLoch, the minimum melt viscosity for maximum impact strength increases continuously as the copolymer approaches the composition of polyacrylonitrile. Thus, the molar composition as well as the molecular weight must be carefully selected if the copolymer is to have the desired mechanical properties. The data for the graphs were determined on the basis of molded pellets because they can be reproduced more easily with regard to changes in the shape. As is known, in order to eliminate distortion, the injection temperature must be increased as the melt viscosity increases. FIG. 5 shows the extent to which the melt viscosity increases with an increasing molar ratio. If the acrylonitrile content of the copolymer is increased, however, the melt stability is reduced, so that the temperature at which the spraying can take place is limited. Ated this ^T varies approximately with the design of the injection mold and the molding machine, but in the majority of injection molding machines used today, the effect occurs that the distortion dee molded part with increasing melt viscosity i m mer is important. Thus, the preferred molar ratio depends on the processing method. In molding and extrusion (where the product is not so inherently distorted) the preferred molar ratio of acrylonitrile to styrene is in the range 3.5 to 5 and is preferably about 4, while the preferred molar ratio in injection molding is in the range 2 to 4 .

For spraying the copolymer itself there is a reduced one Viscosity (measured in the above) of less than 1.0 in preferable in most cases. In the production of films, however, a slightly higher molecular weight can be used as well a higher molar ratio may be desirable. An important

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Application of a copolymer according to the invention is that it is used as a resin component of a mixture with a rubber or a graft copolymer with Rubber substrate.

A copolymer of the present invention can be made by any suitable method for making uniform copolymers will. For example, a method according to British Patent Specification 663,268 using measures used to control the molecular weight of the product. Another, generally more convenient The method is that the copolymer is produced at an approximately constant temperature, if necessary aromatic olefin mixed with acrylonitrile to an acrylonitrile-containing reaction mixture at a rate is added, which is determined by the heat of polymerization released. You amount of heat generated is a more precise information on the amount of polymer formed and thus on the amount of monomer consumed and can by means of isothermal Calorimetry can be measured.

Basically it can be the total amount of heat generated per gram of the polymer formed from the known values of the heat of copolymerization of the monomers or approximately calculated from the known fourths of the heat of homopolymerization of the monomers will. So the maximum amount of heat for complete Polymerization can be predicted in each case. The total amount of monomers to be added can also be used for a 100% copolymer yield with the desired composition can be calculated in advance so that the amount of monomer to be added is calculated which corresponds linearly to a measured amount of heat. In practice, however, it is usually expedient to determine the reaction system empirically according to the relative amounts of monomer and heat to be calibrated so that uniform copolymers of a certain composition are obtained. As a result, there are also any

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Secondary losses of heat from the system take into account that otherwise it would be bothersome to rely only on the heat of copolymerization values calculated values would leave.

The composition of the copolymer depends on the concentration the monomers in the polymerization mixture are very dependent, so the amount of each monomer in the initial batch is decisive is. This can be roughly calculated from published data; however, empirical refinements are made probably be necessary to achieve copolymers with optimal physical properties, for example can be made apparent by obtaining good clear compacts.

For example, around 10Og of a homogeneous copolymer To produce acrylonitrile and styrene is the amount of styrene with the necessary amount of acrylonitrile in the initial batch has been determined empirically for copolymers of various styrene content. The results can be found in the table below. (The rest of the styrene is added continuously during the polymerization) .

Styrene in the Acrylonitrile Styrene Im Start charge Copolymer (cm ³ ) (cm ³ ) (Mole *) 2.1 93.2 15th 2.4 88.6 17.5 2.5 84.0 20th 4.0 68.1 30th

The molecular weight can be determined by using chain transfer agents ^ such as thiols. Preferential

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wisely, part of the chain transfer agent is added to the initial shear and the remainder with the aromatic Fed olefin.

The copolymers according to the invention can thereby be modified that before processing into molded parts, lubricants, Plasticizers, stabilizers, brighteners or fillers, e.g. colloidal rubber particles or glass fibers are added.

The properties of the copolymer can also be modified by copolymerizing one or more additional ethylenically unsaturated monomers with the acrylonitrile and the aromatic olefin. These additional monomers normally only make up a small percentage of the total copolymer, ie less than 10 mol # and usually less than 5 mol # _f , and can generally be added entirely to the initial batch.Vewi the reactivity of the additional monomers compared to that of the acrylonitrile is high , and especially if they are themselves conjugated aromatic olefins, or if relatively large amounts of these monomers are to be added, it may be advantageous to feed the modifying monomers with the main monomer. For example, the polymer can be wholly or partly as aromatic using dibromostyrene Olefin can be made flame retardant. In this case the dibromostyrene would be fed into the reaction vessel with the monomer. By adding a few percent vinyl pyridine the dyeability of the copolymer can be increased. The workability can be increased by adding a few percent of a long chain alkyl vinyl ether, e.g., cetylvinjsther, to the Initially batch to be improved. The point of salvation can can be increased by adding a few percent to the initial batch copolymerizable cyclic compound such as a Maleimide or norbornene derivative, may be added.

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The invention is illustrated below with the aid of some exemplary embodiments explained.

example 1

A homogeneous copolymer of acrylonitrile and styrene with 21.0 mol # of uniformly distributed styrene units (molar ratio of acrylonitrile equal to 3 »76) was made from an initial batch of distilled water (800 cm ⁵ ), acrylonitrile (334 cm ⁵ ), styrene (10 cm ⁵ ), butane-1-thiol (1.67 cm ⁵ ) and sodium dodecyl sulfate (4.0 g). The acrylonitrile and styrene were commercially available substances that were used without further purification. The air in the reaction vessel was removed and replaced with nitrogen. While the reaction vessel was kept at 28 to 34 ⁰ G, an initiator consisting of 7.0 cm of a 5% by weight aqueous ammonium persulphate solution and 7.0 cm of a 4.2% by weight aqueous sodium disulphite solution was added. Then an air-free mixture of styrene and 1-butane-1-thiol (0.56 w / v) was gradually ^{fed in proportions of 0.5 to 1.0 cm 5} linearly with the rate of polymerization (calculated from the rate of heat generation in the reaction vessel). For a 100 # yield of copolymer with 20 mol of styrene units, a total amount of 467 kilojoules was calculated in advance, while the total amount of styrene to be added was 126 cnr in addition to the initial charge.

The course of the reaction is indicated in the table below, the time being given in minutes after the addition of the initiator, the heat being the total heat of polymerization in kilojoules and under "styrene" the total volume (in cm ^:) ) of the in addition to the 10 cnr Styrene of the initial batch of gradually fed styrene is indicated.

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Time warmth Styrene Time warmth Styrene O O 0 98 236 71 29 39 11.5 113 277 84 38 67 19th 126 320 94 45 87 26th 133 345 100 53 110 32 139 364 105.5 61 129 38 145. 389 109 68 151 44 152 404 118.5 76 173 50.5 163 414 122 83 194 57 188 430 126 90 215 64

? Added small amounts of 0.05 wt / vol £ sodium Ifatriumdiaethyldithiocarbaraat wurden'gelegentlich for reaction control when the temperature exceeded 33 ⁰ C. The reaction became noticeably slower after 188 minutes and was then brought to a conclusion by adding 5 parts per volume of 5% by weight sodium dimethyldithiocarbamate.

For the isolation of the copolymer of latex of the reaction vessel into the two-fold volume of vigorously stirred ethanol was poured at about 60 ⁰ C. The coagulum tended to settle if necessary after a little further heating, whereupon the mixture was cooled with stirring and the above liquid was finally poured off. The solid product was washed 4 times by whisking with distilled Waeser at 60 to 70 ⁰ C and finally with cold methanol. Then, it was dried for V'irbelschicht as in an air stream at 80 ⁰ C in a drying oven at 70 ⁰ C for 24 hours and.

The copolymer thus formed had after polymerization of 40 i> of the monomers a 20 mol ^ sodium content of styrene units and a reduced Virscosität of 0 "86 0.5 # in acetic

BATH ORIGINAL

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Solution in dimethylformamide at 25 ⁰ C. The polymer (350 g) of monomer was isolated after consumption of 90 $> containing 21.0 mol £ styrene unit and had a reduced viscosity of 0.89, an impact strength of 6 J / cw? and a Schraelzviscosität of 3 kP at 260 ⁰ O and a shear rate of 1000 / sec.

The properties of the products according to Example 1 can be seen from the upper curves of FIGS. 1, 2 and 3 of the drawings recognize. The properties of certain copolymers are in the table below in order of increasing reduced viscosity indicated.

Mole # styrene 19.8 20.4 22.6 22.4 22, a Molar ratio s
of acrylonitrile 4.05 3.90 3.43 3.47 3.39 reduced vis
cosity 0.56 0.86 0.89 1.08 1.08 Ice cream viscosity 1.4 3.3 3.3 5.4 5.2 Flexural strength
(Jcgf / maS) 19.6 Plied tension 11.0 Impact strength
(j / cm5) 2.7 5.4 5.8 6.1 6.2 Vicat softening
point ( ⁰ C): full
1/10 106
100 108
101 109
103 107
101 105
99

The reduced viscosity, melt viscosity and impact strength were measured as described at the beginning.

The flexural strength was measured using test pieces 51 mm long and 12.7 mm wide obtained from a pressed plate of

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3 on starch were cut out · Dee test piece was on awei studs old 36.1 aa spaced and placed in the middle a wieohen these Stlitaen so loaded that the test piece Kit was bent at a speed of τοη 4.57 aa / ain. The flexural strength was calculated by the fact that the load at the time the fracture old the factor:

(1.5) (58 _# 1) / (12.7) (3) is ^{multiplied by 2} - 0.5.

The Fliefiapension was measured old from a pressed plate of a thickness τοη 3 aa cut test pieces 76 aa long and 14 ma wide. The cross-section in the groove of the test piece was reduced to 9 aa ² Terring by cutting out two slits (radius of curvature of the indan 31 am) opposite one another in the longitudinal edges, so that the narrowest width of the test piece was 3 aa.The test piece was then subjected to tensile stress so that the test piece was elongated at a speed of 12.7 mm / min, and the tension at the streokgrense was observed.

By correspondingly reducing or increasing the amount of tyrene, homogeneous copolymers were used up in other combinations gene produced by the method according to Example 1. Their properties are shown in the table below Order of decreasing molar ratio the acrylonitrile specified:

Mol /, styrene 15.1 18.6 25.0 30.2

Molar ratio 5.62 4.38 3.00 2.31

of acrylonitrile

reduced Vis- 0.97 0.58 0.83 1.20

cosity

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Melt viscosity
(IcP) Example 2 4.4 2.4 2.6 . 3.6 Flexural strength
(kgf / mm2) 20.7 16.1 Impact strength
(Y / emZ) 6-7 2.4 5.4 5.0 Vegan softening
point: ( ⁰ C) full 102 97 102 106 1/10 110 103 109 112

A homogeneous copolymer of acrylonitrile and o-methylstyrene with 19.2 mol £ of evenly distributed oc-methylstyrene units (molar ratio of acrylonitrile s 4.2) was repeated from an initial batch of distilled water (400 cm), acrylonitrile (106 cm ') distilled "-Methylstyrene (5.3 cm ^), sodium sulfate (0.70 g) and octane-1-thiol (0.92 cm ^) prepared starting. The air was removed from the reaction vessel and replaced with nitrogen. While the reaction vessel was kept at 28 "to 35 ^° C., 1.11 g of ammonium pereulfate and 0.925 g of sodium disulfite were added to initiate the reaction, whereupon air-free Cl-methylstyrene in proportions of about 0.5 cm linearly with the rate of polymer isotion ( calculated according to the rate of heat generation in the reaction vessel). The total amount of heat calculated for a 100 pound copolymer yield was 182 kilojoules. The reaction was brought to completion after 340 minutes when the total heat of polymerization was 156 kilojoules. The total volume of diethylstyrene added after the initial batch was 51 »5 cm

Da3 copolymer was isolated as in Example 1 and had a reduced viscosity of 0.79 in 0.5 ^ strength solution in dimethylformamide at 25 ⁰ C and Vicaterweichungspunkten

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of 105 ⁰ C (full) or 96 ⁰ O (1/10). Test pieces were pressed, the previously for 5 minutes at 200 ⁰ C in the mold, an impact strength of 3 J / cnr (as measured as described at the outset).

Example 3

A homogeneous terpolymer of acrylonitrile, styrene and, cetyl vinyl ether with 21 _f 5 mol # of styrene (according to infrared analysis) was made from an initial batch of acrylonitrile (334 enr) _t styrene (10 cm *), cetyl vinyl ether (8 g), sodium lauryl sulfate (4 g), Octane-1-thiol (1.0 cnr) and water (800 cnr) prepared together. The air in the reaction vessel was replaced with nitrogen and the temperature was brought down to about 30 ° C. To initiate the reaction, 7 cnr of a 5 # strength ammonium persulfate solution and 7 cnr of a 4.2 # strength sodium disulfite solution were added. While the temperature was kept approximately constant, a mixture of airless styrene (109t5 cm) and octane-1-thiol (1.34 cm *) was added depending on the heat of reaction generated. The amounts added are shown in the table below, the time being given in minutes, the heat in kilojoules and the volume of styrene in cnr.

After 170 minutes a sample was isolated which had a reduced viscosity of 1.18. The reaction of the remainder was only brought to completion after 290 minutes, after which the polymer v / ie in Example 1 was isolated. The decreased viscosity was 1.05, and the Vicaterweichungspunkte were 1O5 _f 4 ° C (full) ", or 99.8 ⁰ C (1/10). The melt viscosity was 3.7 kP and the extruded body was colorless.

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Time warmth Styrene Since l'änae Styrene O O 0 98 196 58.0 29 39 13.0 109 233 69.0 33 67 17.2 114 256 76.0 58 78 23.5 121 280 82.5 72 97 30.0 128 303 89.0 82 133 40.0 135 322 95.0 87 151 45.5 142 342 101.5 90 169 50.0 151 356 105.0 92 175 51.5 169 370 109.5

Example 4

Following the procedure of Example 1, a homogeneous 3 5-polymer was obtained from acrylonitrile, styrene and H-o ~ Ohlorplienylmaleisiid in an approximate molar ratio of 80: 20: 4.

The initial batch consisted of distilled water (800 cnr), acrylonitrile (264 cm ^), styrene (8.5 ^{~ 3} ), monolorphenyl maleimide (40 g), octane-1-thiol (1 _r 0 cm ') and d Sodium dodecyl sulfate (4.0 g). The air was removed and the polymerization was initiated by adding 17.0% of a 5% by weight aqueous ammonium ^{persulphate solution and 17.0 cm 5 of} a 4.2% by weight aqueous solution of sodium disulphite. The mixture was erwäriat to the reaction tempera door 30 ⁰ G, followed by a mixture of styrene (113 cm ⁵⁾ and octan-1-thiol (1.5 cm ') corresponding to the Polymerisationsgesonwindigkeit was added. After 90 minutes the reaction had slowed down. During that time, 80 era styrene were released. Then 6 cm of a 5% strength by weight aqueous iiatrium diinethyldithiocarbamate solution were added, and the terpolymer was isolated in Example 1. The Terpolyiaer (240 ß) had

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BAD ORiGiNAL,

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.a reduced viscosity of 1.08, an impact strength of 5.5 J / cm and a Vicat softening point of 134 ⁰ C (full).

Example 5

Following the process of Example 1, a homogeneous terpolymer of acrylonitrile, styrene and 5-cyanonorborner was obtained in approximate molar ratio of 80:. 20: 5 established.

The initial batch consisted of distilled water (800 cm), acrylonitrile (264 cm *), styrene (8.5 cm *), 5-cyanonorbornene (30 g) and sodium dodecyl sulfate (4.0 g). The air was removed and the polymerization was carried out by adding 30.0 em3 a 5% by weight aqueous ammonium persulfate solution and

30.0 era- * of a 4 »2 wt / vol ^ aqueous N8triumdisulfitlösung initiated. The mixture was ^{kept at about 30 0} O during the reaction and styrene (70 cnr *) was fed linearly with the rate of polymerization. After 115 minutes, 6 cnr of a 5% by weight aqueous sodium dimethyldithiocarbamate solution were added, whereupon the terpolymer was isolated as in Example 1.

The terpolymer (210 g) had a reduced viscosity of 3.9 », an impact strength of 5.2 J / cm and a Vicat softening point (full) of 124 ° C.

Example 6

A uniform terpolymer of acrylonitrile, styrene and N-vinylcarbazole in a molar ratio of 80: 20: 5 was prepared as in Example 1. The initial batch consisted of acrylonitrile (264 cm '), styrene (8.5 cm), N-vinylcarbaζöl (1.25 g), water (800 units), sodium lauryl sulfate (4 _f 0 g) and octane-1-thiol (1 ml). The air was removed and

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fabric replaced. The temperature was brought to about 30 ⁰ O and kept there during the reaction. A mixture of 14.3 ^J cra a 5 wt / volf'-aqueous Amnioniumpersulfatlösung and 14.3 era a 4.2 wt / vol £ aqueous sodium metabisulfite was added dan. A mixture of styrene (113 cm ⁵ ), octane-1-thiol (1.5 cm ⁵ ) and N-vinylearbazole (47 g) was fed into the reaction mixture according to the rate of polymerization (measured according to the rate of heat generation). The polymer was isolated as in Example 1 in a yield of 148 g. The polymer had a reduced viscosity of 0.96 and a Vicat softening point (full) 120 ⁰ O. "

Claims;

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Claims (2)

Claims 1. A method for the polymerization of acrylonitrile with at least one conjugated aromatic olefin, characterized in that a polymerization reaction mixture containing acrylonitrile and aromatic olefin of the aromatic olefin-containing monomer batch is added at a rate which is determined by the heat of polymerization liberated to form a copolymer of acrylonitrile with evenly distributed units of aromatic olefin, which has a molar ratio of acrylonitrile to aromatic oil units between 2 and 6 and a reduced viscosity (measured at 25 ⁰ O in a 0.5> solution in dimethylformamide) between 0, 5 and 1 _t 2 at a molar ratio less than 4 and between 0.5 and 1.8 at a molar ratio of 4 or more. 2. Copolymer of acrylonitrile and at least one conjugated aromatic olefin, the units of the aromatic olefin being evenly distributed in the polymer molecules, the molar ratio of units of acrylonitrile to units of aromatic olefin in the copolymer being between 2: 1 and 6: 1 and the reduced viscosity of the copolymers (measured in 0.5 # strength solution in dimethylformamide at 25 ⁰ C) is between 0.5 and 1.2, when the Molarvörhältnie less than 4: 1, and 0.5 to 1.8 when the molar ratio is 4 or more. PAWO _m JNO.H.FIHClCE. DIW ING G8ST * K-IM> New documents ιαλ 7 »1 μ». 2 νγ. ι Satt 3 on the And «« · «·» ν. 4. % Md 109833/1570 Blank page